This is only one of 2 known to exist of the original 10 made especially for the OSS during WWII. Acompanying letter.

"The correct ammo for the OSS Pipe was most likely a 'BBC' or Bulleted Breech Cap with a very lightened bullet. It was never admitted historically, but cyanide tipped projectiles were used by my fellow countrymen." - Pete Mason

This specific one was also sent to the production house as the prototype to the one Alan Ladd used in the movie O.S.S.